scholarly journals Bisphenol-Free Epoxy Resins Derived from Natural Resources Exhibiting High Thermal Conductivity

Proceedings ◽  
2020 ◽  
Vol 69 (1) ◽  
pp. 18
Author(s):  
Matthias Sebastian Windberger ◽  
Evgenia Dimitriou ◽  
Frank Wiesbrock
Keyword(s):  
Thermal Conductivity ◽  
Natural Resources ◽  
Polymer Networks ◽  
Sio2 Nanoparticles ◽  
Diglycidyl Ether ◽  
Epoxy Compound ◽  
Inorganic Materials ◽  
Limiting Factor ◽  
Epoxy Amine ◽  
Π Stacking

Polymers commonly have low thermal conductivity in the range of 0.1–0.2 W·m−1·K−1, which is a limiting factor for their usage in the course of continuously increasing miniaturization and heat generation in electronic applications. Two strategies can be applied to increase the transport of phonons in polymers: (i) the embedment of thermally conductive inorganic materials and (ii) the involvement of aromatic units enabling anisotropy by π–π stacking. In this study, the thermal conductivity of resins based on bisphenol A diglycidyl ether BADGE and 1,2,7,8-diepoxyoctane DEO was compared. DEO can be derived from pseudo-pelletierine, which is contained in the bark of the pomegranate tree. The epoxy compounds were cured with isophorone diamine IPDA, o-dianisidine DAN, or mixtures of the both diamines. Notably, isophorone diamine is derived from isophorone of which the latter naturally occurs in cranberries. The formulations were produced without filler or with 5 wt.-% of SiO2 nanoparticles. Significantly enhanced thermal conductivity in the range of 0.4 W·m−1·K−1 occurs only in DEO-based polymer networks that were cured with DAN (and do not contain SiO2 fillers). This observation is argued to originate from π–π stacking of the aromatic units of DAN enabled by the higher flexibility of the aliphatic carbon chain of DEO compared to that of BADGE. This assumption is further supported by the facts that significantly improved thermal conductivity occurs only above the glass-transition temperature and that nanoparticles appear to disrupt the π–π stacking of the aromatic groups. In summary, it can be argued that the bisphenol-free epoxy/amine resin with an epoxy compound derivable from natural resources shows favorably higher thermal conductivity in comparison to the petrol-based epoxy/amine resins.

scholarly journals Temperature-Triggered/Switchable Thermal Conductivity of Epoxy Resins

Polymers ◽  
2020 ◽  
Vol 13 (1) ◽  
pp. 65
Author(s):  
Matthias Sebastian Windberger ◽  
Evgenia Dimitriou ◽  
Sarah Rendl ◽  
Karin Wewerka ◽  
Frank Wiesbrock
Keyword(s):  
Thermal Conductivity ◽  
Polymer Networks ◽  
Diglycidyl Ether ◽  
Epoxy Compound ◽  
Inorganic Materials ◽  
Glass Transition Point ◽  
Limiting Factor ◽  
Epoxy Amine ◽  
Π Stacking ◽  
Enhanced Thermal Conductivity

The pronouncedly low thermal conductivity of polymers in the range of 0.1–0.2 W m−1 K−1 is a limiting factor for their application as an insulating layer in microelectronics that exhibit continuously higher power-to-volume ratios. Two strategies can be applied to increase the thermal conductivity of polymers; that is, compounding with thermally conductive inorganic materials as well as blending with aromatic units arranged by the principle of π-π stacking. In this study, both strategies were investigated and compared on the example of epoxy-amine resins of bisphenol A diglycidyl ether (BADGE) and 1,2,7,8-diepoxyoctane (DEO), respectively. These two diepoxy compounds were cured with mixtures of the diamines isophorone diamine (IPDA) and o-dianisidine (DAN). The epoxy-amine resins were cured without filler and with 5 wt.-% of SiO2 nanoparticles. Enhanced thermal conductivity in the range of 0.4 W·m−1·K−1 was observed exclusively in DEO-based polymer networks that were cured with DAN (and do not contain SiO2 fillers). This observation is argued to originate from π-π stacking of the aromatic units of DAN enabled by the higher flexibility of the aliphatic carbon chain of DEO compared with that of BADGE. The enhanced thermal conductivity occurs only at temperatures above the glass-transition point and only if no inorganic fillers, which disrupt the π-π stacking of the aromatic groups, are present. In summary, it can be argued that the bisphenol-free epoxy-amine resin with an epoxy compound derivable from natural resources shows favorably higher thermal conductivity in comparison with the petrol-based bisphenol-based epoxy/amine resins.

scholarly journals Excellent Performances of Composite Polymer Electrolytes with Porous Vinyl-Functionalized SiO2 Nanoparticles for Lithium Metal Batteries

Polymers ◽  
2021 ◽  
Vol 13 (15) ◽  
pp. 2468
Author(s):  
Hui Zhan ◽  
Mengjun Wu ◽  
Rui Wang ◽  
Shuohao Wu ◽  
Hao Li ◽  
...  
Keyword(s):  
Polymer Electrolytes ◽  
Specific Capacity ◽  
Sio2 Nanoparticles ◽  
Inorganic Materials ◽  
Solid Polymer Electrolytes ◽  
Lithium Metal ◽  
Composite Polymer ◽  
Composite Electrolyte ◽  
Composite Polymer Electrolytes ◽  
Lithium Metal Batteries

Composite polymer electrolytes (CPEs) incorporate the advantages of solid polymer electrolytes (SPEs) and inorganic solid electrolytes (ISEs), which have shown huge potential in the application of safe lithium-metal batteries (LMBs). Effectively avoiding the agglomeration of inorganic fillers in the polymer matrix during the organic–inorganic mixing process is very important for the properties of the composite electrolyte. Herein, a partial cross-linked PEO-based CPE was prepared by porous vinyl-functionalized silicon (p-V-SiO2) nanoparticles as fillers and poly (ethylene glycol diacrylate) (PEGDA) as cross-linkers. By combining the mechanical rigidity of ceramic fillers and the flexibility of PEO, the as-made electrolyte membranes had excellent mechanical properties. The big special surface area and pore volume of nanoparticles inhibited PEO recrystallization and promoted the dissolution of lithium salt. Chemical bonding improved the interfacial compatibility between organic and inorganic materials and facilitated the homogenization of lithium-ion flow. As a result, the symmetric Li|CPE|Li cells could operate stably over 450 h without a short circuit. All solid Li|LiFePO4 batteries were constructed with this composite electrolyte and showed excellent rate and cycling performances. The first discharge-specific capacity of the assembled battery was 155.1 mA h g−1, and the capacity retention was 91% after operating for 300 cycles at 0.5 C. These results demonstrated that the chemical grafting of porous inorganic materials and cross-linking polymerization can greatly improve the properties of CPEs.

scholarly journals Thermoelectric Materials for Textile Applications

Molecules ◽  
2021 ◽  
Vol 26 (11) ◽  
pp. 3154
Author(s):  
Kony Chatterjee ◽  
Tushar K. Ghosh
Keyword(s):  
Thermal Conductivity ◽  
Carbon Nanotubes ◽  
Seebeck Coefficient ◽  
Thermoelectric Materials ◽  
Figure Of Merit ◽  
Inorganic Materials ◽  
Peltier Effect ◽  
Electronic Textiles ◽  
Heating And Cooling ◽  
Recent Attention

Since prehistoric times, textiles have served an important role–providing necessary protection and comfort. Recently, the rise of electronic textiles (e-textiles) as part of the larger efforts to develop smart textiles, has paved the way for enhancing textile functionalities including sensing, energy harvesting, and active heating and cooling. Recent attention has focused on the integration of thermoelectric (TE) functionalities into textiles—making fabrics capable of either converting body heating into electricity (Seebeck effect) or conversely using electricity to provide next-to-skin heating/cooling (Peltier effect). Various TE materials have been explored, classified broadly into (i) inorganic, (ii) organic, and (iii) hybrid organic-inorganic. TE figure-of-merit (ZT) is commonly used to correlate Seebeck coefficient, electrical and thermal conductivity. For textiles, it is important to think of appropriate materials not just in terms of ZT, but also whether they are flexible, conformable, and easily processable. Commercial TEs usually compromise rigid, sometimes toxic, inorganic materials such as bismuth and lead. For textiles, organic and hybrid TE materials are more appropriate. Carbon-based TE materials have been especially attractive since graphene and carbon nanotubes have excellent transport properties with easy modifications to create TE materials with high ZT and textile compatibility. This review focuses on flexible TE materials and their integration into textiles.

Wear Based Lifetime Estimation of a Clutch Facing using Coupled Field Analysis

2021 ◽  
Vol 18 (4) ◽  
Author(s):  
A. Kulkarni ◽  
R. Mahale ◽  
C. Kannan
Keyword(s):  
Working Life ◽  
Element Model ◽  
Friction Material ◽  
Inorganic Materials ◽  
Field Analysis ◽  
Frictional Heat ◽  
Ride Quality ◽  
Wear Loss ◽  
Limiting Factor ◽  
The Impact

Repetitive use of the clutch, over a period of time, causes the friction material at the contact surfaces (clutch facing and flywheel/pressure plate) to wear, thus deteriorating its performance and usable life. The working life of a rigid clutch is the limiting factor when it comes to extracting maximum performance from a dual mass flywheel system, which is used in a lot of modern vehicles nowadays to lower fuel consumption and improve ride quality. In this study, we investigate the influence of different groove patterns on wear in rigid clutch facings and estimate their life using a comprehensive finite element model. The wear is calculated and analysed for five different groove patterns across two different inorganic materials, namely FTL180 and TF1600-MC2, using Archard’s Adhesive Wear Model. Coupled multi-physics elements are employed in the analysis to capture the effect of frictional heat generation on wear. We found that the Waffle pattern offered a decrease of 10.4% in volumetric wear loss, a 5.78% decrease in maximum wear thickness and an increase of 11.51% in the average working life is used in city like conditions with frequent engagements. This work sheds light on the impact of groove patterns on clutch facing wear and opens a new path for the design and development of more resilient rigid clutches.

scholarly journals Build-To-Specification Vanillin and Phloroglucinol Derived Biobased Epoxy-Amine Vitrimers

Polymers ◽  
2020 ◽  
Vol 12 (11) ◽  
pp. 2645
Author(s):  
Aratz Genua ◽  
Sarah Montes ◽  
Itxaso Azcune ◽  
Alaitz Rekondo ◽  
Samuel Malburet ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Renewable Resources ◽  
Diglycidyl Ether ◽  
Vanillyl Alcohol ◽  
Molecular Architecture ◽  
Covalent Bonds ◽  
Thermoset Resins ◽  
Epoxy Amine ◽  
Reversible Covalent ◽  
Epoxy Matrices

Epoxy resins are widely used in the composite industry due to their dimensional stability, chemical resistance, and thermo-mechanical properties. However, these thermoset resins have important drawbacks. (i) The vast majority of epoxy matrices are based on non-renewable fossil-derived materials, and (ii) the highly cross-linked molecular architecture hinders their reprocessing, repairing, and recycling. In this paper, those two aspects are addressed by combining novel biobased epoxy monomers derived from renewable resources and dynamic crosslinks. Vanillin (lignin) and phloroglucinol (sugar bioconversion) precursors have been used to develop bi- and tri-functional epoxy monomers, diglycidyl ether of vanillyl alcohol (DGEVA) and phloroglucinol triepoxy (PHTE) respectively. Additionally, reversible covalent bonds have been incorporated in the network by using an aromatic disulfide-based diamine hardener. Four epoxy matrices with different ratios of epoxy monomers (DGEVA/PHTE wt%: 100/0, 60/40, 40/60, and 0/100) were developed and fully characterized in terms of thermal and mechanical properties. We demonstrate that their performances are comparable to those of commonly used fossil fuel-based epoxy thermosets with additional advanced reprocessing functionalities.

Processing of Polymers and Polymer Composites In a Microwave Applicator

1990 ◽  
Vol 189 ◽  
Author(s):  
Martin C. Hawley ◽  
Jianghua Wei
Keyword(s):  
Polymer Composites ◽  
Reaction Rates ◽  
Diglycidyl Ether ◽  
Flexural Properties ◽  
Diaminodiphenyl Sulfone ◽  
Epoxy Amine ◽  
Thin Film Technique ◽  
Microwave Applicator ◽  
Heating Mode ◽  
Resonant Heating

ABSTRACTPolymers and polymer composites have been processed In a cylindrical resonant microwave applicator at a frequency of 2.45GHz. Stoichlometric mixtures of two epoxy/amine systems, DGEBA (Diglycidyl Ether of Bisphenol A)/DDS (4,4'-Diaminodiphenyl Sulfone) and DGEBA/mPDA(m-Phenylene Diamine), were microwave and thermally cured Isothermally using a thin film technique. FTIR was used to determine the extent of cure. Increased reaction rates were observed In microwave cure when compared to those of thermal cure. The rate Increase due to microwave effects was much greater for the DGEBA/DDS system than for DGEBA/mPDA. Also, crossply and unidirectional 24-ply and 72-ply graphite/epoxy laminates(AS4/3501-6 prepreg, Hercules Corp.). were processed using microwave radiation. The flexural properties of the microwave processed composites were strongly dependent on the resonant heating mode. Comparable flexural properties were obtained for the unpressurized microwave processed composites and the pressurized autoclave processed composites. Proper controlled-hybrid modes are required to process composites of high mechanical properties. The procedures for obtaining these controlled-hybrid modes are described.

scholarly journals Crop Residues Management under Changing Climate Scenario

2021 ◽  
pp. 21-28
Author(s):  
May Zar Myint ◽  
Raihana Habib Kanth ◽  
F. A. Bahar ◽  
S. S. Mehdi ◽  
A. A. Saad ◽  
...  
Keyword(s):  
Soil Erosion ◽  
Sustainable Agriculture ◽  
Natural Resources ◽  
Agricultural Sector ◽  
Crop Residues ◽  
Soil Surface ◽  
Residue Management ◽  
Limiting Factor ◽  
Natural Ecosystem ◽  
The Impact

Soil is the fundamental and necessary natural resource for the agricultural production system. Due to the increasing global population and the impact of climate changes, natural resources are the major limiting factor to use widely for food production. The major factors responsible for the deterioration of natural resources are extreme events caused by man-made activities and unexpected and unpredictable adverse natural forces of nature. Among the different degradation processes, soil erosion is one of the serious threatens to the deterioration of soil for the agricultural sector and healthy ecosystem conservation. Intensive agricultural practices are particularly caused by the acceleration of the soil erosion process. Therefore, the good and systematic management of soil resources is indispensable not only for sustainable agriculture or conservation agriculture but also for the protection and reduction of the natural ecosystem. Covering crop residues on soil enhances organic matter, protects the soil surfaces, maintains water and nutrients, improves soil biological activity and chemical composition, and contributes to pest management. Therefore, crop residue management is one of the conservation practices and is designed to leave sufficient residue on the soil surface to reduce wind and water erosion. It includes all field operations that affect the amount of residue, its an orientation to the soil surface and prevailing wind and rainfall patterns and the residue distribution throughout the period requiring protection. This paper especially highlights the status of soil erosion, crop residues, and management in crop residues in sustainable agriculture.

scholarly journals Selection of structural elements of cross-linked polymers used in construction

Vestnik MGSU ◽  
2021 ◽  
pp. 347-359
Author(s):  
Andrey A. Askadskii ◽  
Sergey V. Matseevich ◽  
Tat’yana A. Matseevich
Keyword(s):  
Thermal Conductivity ◽  
Glass Transition ◽  
Computer Program ◽  
Water Permeability ◽  
Polymer Network ◽  
Polymer Networks ◽  
Physical Characteristics ◽  
Network Polymers ◽  
Optical Coefficient ◽  
Selection Of

Introduction. For the first time, a model and a principle for constructing an appropriate computer program for the selection of polymer networks with a given interval of a number of physical characteristics are proposed. These characteristics include density, the temperature of the onset of intense thermal degradation, thermal conductivity, water permeability, and the stress-optical coefficient. As an example, 16 smallest base fragments are given, which, when attached to each other, allow the selection of structural fragments of repeating fragments of polymers of the following classes: polyolefins, vinyl polymers, polystyrene, polyamides, polyethers and polyesters, polycarbonates, polyetherketones, polyimides, polysulfides, polysulfones, silicone polymers, polyurethanes, cellulose derivatives, methacrylic polymers, etc. The purpose of the study is to develop a model for writing a computer program that allows the selection of structural fragments of network polymers possessing specified intervals of physical characteristics. For polymers used in the construction industry, the most important are the glass transition temperature, the stress-optical coefficient, density, water permeability, and thermal conductivity. Materials and methods. A repeating fragment of the network is selected from the smallest basic fragments, which are connected to each other using a control matrix of interactions. The matrix contains labels that allow you to control the interaction of carbon with three carbon atoms, with a carbon atom and two nitrogen atoms, with two carbon atoms and one oxygen atom, with two carbon atoms and one nitrogen atom, with four carbon atoms. There are also labels that control the interaction of carbon atoms included in the aromatic cycles with two carbon atoms and one oxygen atom, with four carbon atoms, with four nitrogen atoms, with two carbon atoms and one sulfur atom, and three oxygen atoms. This makes it possible to select a huge amount of cross-linked polymer. Results. As an example, the possible chemical structure of 14 cross-linked nodes of the polymer network is presented and the corresponding calculations are carried out, showing the adequacy of the model and the principle of constructing a computer program. The structures of the five cross-linked nodes of polymer network were used and the following physical characteristics of the resulting networks were calculated: density, the temperature of the onset of intense thermal degradation, water permeability, thermal conductivity, and the stress-optical coefficient. All these characteristics are important for the manufacture of building materials. Conclusions. The results of the work allow us to write a real computer program for the selection of repeating fragments of polymer networks that have a given interval of a number of important physical characteristics of network polymers. Among these characteristics are not only those listed above, but also other characteristics, such as glass transition temperature, Hildebrand solubility parameter, surface energy, heat capacity, intermolecular interaction energy, permittivity, etc.

Synthesis of new copolymers 4,4’-sulfinylbisphenol derivative with N-vinyl-2-pyrrolidone - photopolymerization and thermo-mechanical studies

e-Polymers ◽  
2012 ◽  
Vol 12 (1) ◽  
Author(s):  
Beata Podkościelna ◽  
Andrzej Bartnicki ◽  
Barbara Gawdzik
Keyword(s):  
Liquid System ◽  
Diglycidyl Ether ◽  
Epoxy Compound ◽  
Mechanical And Thermal Properties ◽  
Before And After ◽  
Triethylbenzylammonium Chloride ◽  
Ft Ir ◽  
Two Phases ◽  
New Compounds

AbstractSynthesis, structure and characterization of the new sulfur monomer sulfinylbis[benzene-4,1-diyl(oxy-2-hydroxypropane-3,1-diylmethacrylate)] (SO.DM) and its photopolymerization with N-vinyl-2-pyrrolidone (NVP) are presented. SO.DM was obtained in the three-step reaction. In the first step, 4,4’- sulfinylbisphenol from 4-[(4-hydroxyphenyl)thio]phenol was obtained. In the second step the epoxy compound was synthesized. It was obtained in the reaction of 4,4’- sulfinylbisphenol with 2-(chloromethyl)oxirane in the two phases liquid/liquid system including organic and aqueous phases. In the third step, ring opening of the obtained diglycidyl ether was carried out with the use of methacrylic acid in the presence of triethylbenzylammonium chloride (TEBAC) as a catalyst. Structures of new compounds were confirmed by spectroscopic methods (FT-IR, 1H and 13CNMR and DIP-MS). Photopolymerization of compositions containing different ratios of the monomers (SO.DM and NVP) and an initiator (Irgacure 651) was carried out. The following properties (before and after curing) were determined: density, polymerization shrinkage, glass transition temperature, Young’s modulus, hardness, tensile strength. Moreover, dynamic-mechanical and thermal properties were studied.

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